A method for realizing a single large-sized screen by use of at least two displays has been used for a large size display device. Generally, a flat display is used for a portable display device. An LCD (Liquid Crystal Display), an FED (Field Emission Display), a PDP (Plasma Display Panel), an EL (Electro Luminescent) are well known as the flat display.
In recent years, since new functions such as a wireless Internet have been added to the portable display device, a display device having a large-sized screen has been required. However, such a large-sized portable display has a problem of its mobility due to its overall size. To overcome this problem, a foldable multi-display device has been proposed.
In the foldable multi-display device, more than two displays are interconnected to be foldable, but not separable. That is, the separation and connection of the displays cannot be flexibly realized. For example, it is impossible for a user to carry only one display, deteriorating the mobility and convenience that are the inherent properties of the portable display device.